Vault Projections

In the following drawing and design exercise, a foreshortened bay at the Church of the Jacobins becomes a significant formal entity that informs a series of projective drawings. Departing from the precedent analysis, this exercise ultimately produces a formally related object.

Church of the Jacobins ChevetToulouse, France (18th century)

CHURCH OF THE JACOBINS

The Church of the Jacobins, built by the Dominican Order in the early-mid 13th century in Toulouse, France is a unique example of late-Gothic style. The church was built in four phases; each successive plan building upon the previous design either by maintaining or discarding particular proportions and geometry.

The first church plan, completed 1235, was erected on a site that encouraged a structure that was long and wide. This site-specific configuration, along with the Dominican Order’s lack of funds led to the original design that featured a flat wooden roof, supported by an internal asymmetric colonnade. The presence of the colonnade running the length of the church produced an intriguing dual-nave and asymmetric plan. Subsequent phases of construction included a two-bay extension of the flat roof wooden structure in 1252, as well as the addition of a radially symmetric star-vault and repositioning of column centers in 1390. The present day Church of the Jacobins continues to feature a largely symmetric design, however, upon close inspection a truncated bay between the church chevet and main body lingers as a clue to the set of vestigial proportions that have driven the design and construction of the church throughout history.

FORMAL ANALYSIS OF REFLECTED CEILING PLAN

The adjacent sequence of diagrams illustrate shifting geometries and proportional relationships present within the nave of the Church of the Jacobins throughout history. Beginning in Phase I, a distinctly asymmetric colonnade is constructed. The initial bay depth “C” is establish and informs, in Phase II, proportions of a two-bay flat roof addition. In Phase III, an additional chevet extension is added to the main body with proportions derived bay-width proportion “B.” In Phase IV, an ambitious design proposal is established which aims to vault the entire church and impose an alternate set of proportions to produce a largely symmetric double-height space. Ultimately, in Phase V, a vaulted design is constructed that includes a shifted symmetric colonnade, as well as a radially symmetric star-vault with a bay width determined by the proportion and corresponding star-vault radius, “R.” At the intersection of the chevet and main body, a single vestigial asymmetric proportion “C” is preserved and operates as an interesting moment of tension and transition.

Re-Introducing Assymetry

Situated directly between the chevet and apse, the foreshortened bay at the Church of the Jacobins remains a significant formal entity that has become increasingly muted in recent planometric iterations. The diminished presence of the truncated bay is a due in part to the gradual imposition of symmetry on the church’s double-nave plan. A column and boundary change within the church chevet is executed in order to reintroduce asymmetry to the church plan. Upon performing the shifts to half of a vault fragment, scalar changes can be measured in both plan and in section. Additionally, more subtle effects are produced at the scale of the fragment’s ribs and voussoirs. The slight skewing of the in the vault fragment’s voussoir and rib proportions affect the overall geometry of each piece and affect the logic and stability of their assembled positions.

Transverse bay-width proportion “R” (Phase V ) is extended to initiate a return to a more asymmetrical chevet plan. The proportion “R” is lengthened to match a precursor asymmetric transverse bay-width proportion “B” (Phase I-III). In lieu of placing the star-vault central column at radius “R” (Phase V) the above super-imposition illustrates changes in the chevet proportions and geometry when the column is shifted and to match foreshortened bay-depth proportion “C” (Phase I-III).

PROJECTED OBJECT TECHNIQUE

A projection technique is initiated, first, by distilling center points from the vault voussoirs and then extracting arcs from the vault ribwork.

Lines are projected from the voussoir center points and extended normal to the curvature of the extracted arcs. All voussoir center points are projected in a linear fashion towards the center of the corresponding vault. The projected lines eventually intersect and, when read together, the collection of lines began to form an implied curve.

To visualize the space between the projected lines, neighboring lines are lofted to create a series of overlapping planes. At points of intersection an implied surface is produced via the assemblage of planar surfaces.